Steins;Gate is receiving a sequel in the form of Steins;Gate Zero, described as the “true sequel” for the franchise by top developer Chiyomaru Shikura – and fans of the anime rather than the VN will be happy to hear an anime is apparently in the works too.

https://www.youtube.com/watch?v=zfFC15WoNYo

"Text: November 2010, in the Beta world line
Text: This is the story after Rintaro Okabe was not able to save "her" on July 28.
Text: The "him" of this time didn't know that a system called "AMADEUS" would lead the world into a state where conspiracy once again runs rampant.
Text: Yes, "she" is still there... "

I am assuming another story from the perspective of the "one" who gave Okabe the 2 big clues he needed near the end of the first season. I am guessing it will be that one's research, as well as stuff that follows afterwards. Things that he did not expect, such as "AMADEUS", as it stated in the PV.